Update ext/ModelingToolkitUnitfulExt.jl

Author: ChrisRackauckas

ext/ModelingToolkitUnitfulExt.jl

@@ -20,7 +20,7 @@ function MT._get_unittype(u::Unitful.Unitlike)
     return Val(:Unitful)
 end
 
-MT._oneunit(x::Unitful.FreeUnits) = x(1)
+MT._oneunit(x::Unitful.FreeUnits) = 1 * x
 
 # Base operations for mixing Symbolic and Unitful
 Base.:*(x::Union{MT.Num, Symbolic}, y::Unitful.AbstractQuantity) = x * y